In heavily gerrymandered Texas, only about a dozen seats in the 150-member House are considered competitive this year.

Still, the number of close races is higher than in most recent years, and Democrats looking for upsets against incumbent Republicans — mostly in big cities and their suburbs — have presidential nominee Donald Trump to thank for it.

Democrats are banking on the prospect that a poor performance by Trump, higher voter turnout for a presidential election and the state's ongoing demographic shift can coalesce into a handful of victories for the underdog party.

That’s the consensus of political scientists and campaign operatives from both parties interviewed by the Tribune in the final weeks of the 2016 campaign in Texas, where polls show Trump’s lead is far smaller than normal for a Republican presidential hopeful in the deep-red state. Recent polls indicate Democratic presidential candidate Hillary Clinton is trailing Trump by as few as three points in Texas, and optimistic Democrats hope to turn that into a down-ballot advantage.

“The $64,000 question is, do Republicans who don’t want to support Trump turn out at all?” asked GOP consultant Matt Mackowiak, referring to the 1950s game show. For Republicans, he said, “I think what’s true is that we’re not going to have the straight-ticket advantage that we’ve had.”

The Texas House currently has 99 Republicans, 50 Democrats and one independent. Democrats typically have seen their ranks shift up or down by about half a dozen every two years. After the 2012 election, Democrats sent 55 members to the Texas House. After the 2010 election, 49 Democrats were sworn in to the Legislature's lower chamber.

“The $64,000 question is, do Republicans who don’t want to support Trump turn out at all?”— GOP consultant Matt Mackowiak

Texas Democrats hoping to leverage Trump’s relative unpopularity in Texas acknowledge the minority party’s long odds when it comes to flipping more than a handful of seats. Republican candidates by and large hold massive fundraising leads.

“It’s certainly exciting to see single-digit polls repeatedly in Texas, but we look at this situation with very clear eyes,” said Manny Garcia, deputy executive director of the Texas Democratic Party. “We know that our challenge is to build permanent infrastructure for the future, for every single cycle, and to make sure that all Democratic campaigns can be competitive in the future.”

Brandon Rottinghaus, a political science professor at the University of Houston, said Democrats’ “best-case scenario” would be to pick up four or five state House seats this year. Changing demographics in Texas' more urban districts favor Democrats in a presidential year, he said, and Trump's unpopularity with women could also drive women voters to support female legislative candidates.

“This is a win on the battlefield, but just one event in the larger war,” Rottinghaus said in an email. “Winning in midterm elections with no presidential candidate at the top of the ticket will be the real test of the party’s strategy.”

Still, even if Democrats enjoy sweeping victories in their competitive races, Rottinghaus said, Republicans will still easily control the chamber. It's unlikely Democratic wins would translate into major legislative victories at the state Capitol next year, and there wouldn’t be “much change in the tone or tactics” of the House overall, he said.

For Republicans in close races, the challenge has been to walk the tightrope of running on a conservative political record without aligning too closely with Trump.

Texas House Speaker Joe Straus, an early supporter of former Republican presidential candidate Jeb Bush, has not endorsed Trump. A Straus spokesman said last week the speaker is busy focusing on fundraising and other efforts to back Republican incumbents.

"House Republicans have a good record to run on, and Speaker Straus enjoys helping his colleagues share that record in their communities," spokesman Jason Embry said in an email.

Sheets, the Republican incumbent from Dallas, told the Tribune this weekend that when he talks to voters, Trump “rarely comes up.”

“When we look at races and when we go into election cycles, you need to clearly understand that the maps are very sophisticatedly designed for Democrats to lose.”— Manny Garcia, deputy executive director of the Texas Democratic Party

“Because of this, we get to talk about issues like economic growth, securing our border, protecting our communities and creating job opportunities for the hard-working middle class,” he said.

Peña, the Pasadena Republican, told The Texas Tribune he didn't think Trump's presence at the top of the ticket would "make any difference."

"Neither candidate is well-liked," he said of the presidential contenders.

Mackowiak said it's possible that down-ballot Republicans could be isolated from some of the Trump fallout. He predicted straight-ticket voting for a single party would be “the lowest we’ve ever seen this cycle.”

“My general sense is that down-ballot candidates who run really good races ... can generally over-perform a with headwind at the top of the ballot — I’d say in a six- to eight-point range,” he said. “You start getting beyond 10 points, in that range, it’s just too much to make up.”

Garcia said Texas Democrats were hopeful going into November, but that the way electoral districts are drawn continues to put the state’s underdog party at a disadvantage.

“When we look at races and when we go into election cycles, you need to clearly understand that the maps are very sophisticatedly designed for Democrats to lose,” he said.